Data from: Coping with strong variations in winter severity: plastic habitat selection of deer at high density

Few empirical studies on large herbivores considered how behavioral plasticity could enhance their capacity to cope with rapid and extreme changes in weather conditions at several spatiotemporal scales. During winter, large herbivores living under low predation pressure mainly trade-off benefits of forage acquisition with the costs of exposure to harsh weather conditions. We assessed the changes in this trade-off for white-tailed deer adult females on Anticosti Island (Canada) at different scales during 2 contrasted winters (i.e., a harsher and a milder winter). We hypothesized that deer should adjust their foraging decisions to avoid cold wind-chill temperatures and high locomotion costs in deep snow as winter severity increased. We compared habitat selection at the home-range scale, habitat selection relative to thermal conditions within the home range, and selection for foraging sites relative to snow conditions along the foraging tracks between winters. Home-range selection of deer was similar between winters. Deer adjusted their within-home-range selection relative to thermal conditions: they selected thermal cover during cold-stress periods while their selection for open areas increased during the warmer periods. Deer showed high behavioral plasticity along their foraging tracks: they selected tracks with different forage resources between winters and traded-off the locomotion costs in deep snow cover with the benefits of forage availability as winter severity increased. We discuss how behavioral plasticity of deer in their thermoregulatory behavior and foraging site selection allows them to cope with varying winter conditions, in a system where their short-term behavioral adaptations were already strongly constrained by intraspecific competition.

目前针对大型有蹄类动物的实证研究中，鲜有探讨行为可塑性如何提升其在多时空尺度下应对快速极端天气变化的能力。冬季时，捕食压力较低的大型有蹄类动物通常会在获取食物的收益与暴露于恶劣天气的代价之间进行权衡。本研究以加拿大安蒂科斯蒂岛的成年雌性白尾鹿为对象，在两个差异显著的冬季（分别为严寒冬季与暖冬）中，从多个尺度评估了这类权衡关系的变化。我们提出假设：随着冬季严酷程度升高，白尾鹿会调整其觅食决策，以规避风寒低温与深雪中高昂的移动能耗。我们比较了两个冬季间，白尾鹿在以下三类选择上的差异：家域尺度的生境选择、家域内与热环境相关的生境选择，以及沿觅食路径上与积雪条件相关的觅食位点选择。不同冬季间，白尾鹿的家域选择并无显著差异。白尾鹿会根据热环境调整家域内的生境选择：在冷应激时段，它们会选择保温遮蔽栖息地；而在较为温暖的时段，对开阔区域的选择占比则会提升。白尾鹿在觅食路径上表现出较强的行为可塑性：两个冬季间，它们会选择具备不同食物资源的路径；且随着冬季严酷程度升高，会在深积雪环境下的移动代价与食物可获得性带来的收益之间进行权衡。我们还探讨了，在该研究系统中，白尾鹿的体温调节行为与觅食位点选择所体现的行为可塑性，如何帮助其应对多变的冬季环境——而在此系统中，它们的短期行为适应已受到种内竞争的强烈制约。